CVE-2026-114478 Confused deputy en el reenvío de hMailServer

Qué es CVE-2026-114478

El reenvío de hMailServer no preserva adecuadamente el remitente original, permitiendo que un atacante remoto no autenticado envíe correo con un From de un dominio alojado y que llegue a otros destinatarios como si cumpliera la política DMARC de ese dominio. Afecta a hMailServer 6.0.0 hasta 6.3.6.

Productos y versiones afectadas

• Progressive Robot Ltd hMailServer

  • desde 6.0.0 hasta 6.3.6

Qué hacer

1. Verificá si usás hMailServer y en qué versión: el rango afectado figura arriba.
2. Actualizá a la versión corregida que indique el fabricante en su aviso (ver referencias) o aplicá la mitigación que publique.
3. Revisá registros y accesos de los sistemas expuestos para descartar que se haya aprovechado antes de corregir.

Calculadora CVSS

CVSS 3.1 · 5.9 MEDIA

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

VECTOR DE ATAQUE (AV)

Red

COMPLEJIDAD DEL ATAQUE (AC)

Alta

PRIVILEGIOS REQUERIDOS (PR)

Ninguno

INTERACCIÓN DEL USUARIO (UI)

Ninguna

ALCANCE (S)

Sin cambio

CONFIDENCIALIDAD (C)

Ninguna

INTEGRIDAD (I)

Alta

DISPONIBILIDAD (A)

Ninguna

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Descripción original

Insufficient preservation of the original sender in the forwarding of Progressive Robot hMailServer 6.0.0 through 6.3.6 allows a remote unauthenticated attacker to have mail they write, naming in its From an address at a domain the server hosts, delivered to other receivers as passing that domain's DMARC policy. When the server sent on a copy of mail that came from outside - an account's forward, a mail rule's forward, a Sieve redirect, a list's copy, or an alias or list expanding to an outside address - it could give the copy an SMTP identity in the organisation of the domain the copy's From names, whatever the message's origin: with the Sender Rewriting Scheme or the rewrite of the envelope sender on forwarding enabled (both off by default), an address at the forwarding domain; for a list, its bounce address; for a message with an empty envelope sender, none, under the server's own host name; and an envelope sender the message came with at a subdomain of a hosted domain was kept. Where that identity's SPF record authorises the server, other receivers' SPF check of the copy passed for a domain aligned with the From, and DMARC passed with it, although the message had not passed DMARC when the server received it. Exploitation needs a forward, redirect, alias or list that carries the hosted domain's mail to an outside address, and one of: SRS or the envelope rewrite enabled; a list whose bounce address is in the domain's organisation; an envelope sender at a subdomain whose SPF record authorises the server; or, for an empty envelope sender, an SPF record that authorises the server under its host name. The DKIM route to the same result is CVE-2026-107567.

Referencias

• gitlab.com/hmailserver/hmailserver/-/work_items/90
• gitlab.com/hmailserver/hmailserver/-/releases/v6.3.7

Historial de la alerta

1. 21 OCT · 14:45VULNERABILIDAD Nueva vulnerabilidad detectada.

CÓMO SE HIZOResumen traducido automáticamente al español a partir de la descripción original. Ante dudas, la descripción original y las referencias del fabricante son la fuente de verdad. Cómo funciona.